1. Field of the Invention
The present invention relates to a magnetic type agitator for mixing different liquids or liquid with pulverized material, and more particularly to such an agitator which permits transmission of ultrasonic wave into liquid while being agitated.
2. Description of the Prior Art
As is well known, mixing and agitating of different liquids or liquid with pulverized material is performed widely in chemical, medicine, food, agricultural or agricultural technology industries. For example, it is desired that liquid is homogenized, or a desired ph-control is attained.
Radiation of ultrasonic wave into a solution causes cavitation therein, which is useful in performing different treatments on the solution. For example, ultrasonic wave is radiated into a solution having pulverized material suspended therein, causing cavitation in the solution to reduce particle size and provide a homogenized solution. For another example, ultrasonic wave is radiated into a solution to cause cavitation therein, and the heat caused by cavitation is used to expedite oxidation or deoxidization of the solution, thus modifying some ingredients of the solution, or ionizing selected components of the solution to control the degree of ionization of the whole solution. The mechanisms in these processes are not known, but ultrasonic energy has been used widely in different industrial fields.
Usually in mixing different liquids or liquid with pulverized material, a magnetic type agitator is used. A magnetic agitating element is put in a magnetically permeable vessel which contains different liquids, or liquid and pulverized material, and a rotating magnetic plate is made to rotate below the bottom of the vessel, thereby causing the magnetic agitating element to rotate in the vessel and agitate the bath.
Magneto- or electro-striction is used to radiate ultrasonic wave into a solution, thereby causing cavitation therein. A vessel has magneto- or electro-striction elements attached to its bottom or side walls.
In case where one and same object is subjected to agitation by a magnetic type agitator, and ultrasonic treatment by an ultrasonic wave generator, it is subjected to agitation and ultrasonic treatment at different places and times. In an attempt to subject an object simultaneously to these different treatments, an electro-striction element is placed adjacent to the rotating magnetic plate of the magnetic type agitator. In this arrangement, however, the electro-striction element may constitute an obstacle against rotation of the rotating magnetic plate. Electro-striction elements when attached to the side wall surface of the cylindrical vessel will constitute no obstacle, but it is difficult to attach the relatively flat surface of the electro-striction element to the curved surface of the cylindrical vessel.
As described earlier, it is difficult to combine magnetic type agitator and ultrasonic wave generator, and therefore, they are used separately in treating one and same object. In this connection there are some inconveniences and disadvantages as for instance, follows:
Agitation by a magnetic type agitator is followed by cavitation caused by an ultrasonic wave generator. Thus, the advantageous effect caused by agitation cannot be simultaneously combined with the advantageous effect caused by cavitation. In case where an electro-striction element is attached to the side of the vessel of a magnetic type agitator, the physical irregularity or unfitness between the flat electro-striction element and the curved surface of the vessel will cause uneven transmission of ultrasonic wave in the bath, and still disadvantageously whether ultrasonic wave can travel in the bath or not, depends on the level of solution. Thus, in fact, this composite structure is impractical.